Synthesis of benzaldehydes

ABSTRACT

Novel benzaldehydes of the formula: ##STR1## Where n 1  is the integer 1-8 and each OR 1  group is hydroxy or a protective group which can be converted or removed to provide the dihydroxyphenyl moiety. 
     The benzaldehydes are particularly useful as intermediates in the preparation of yellow azomethine dye developers.

CROSS REFERENCE TO RELATED CASES

This application is a continuation of prior copending application Ser.No. 856,220, filed Dec. 1, 1977 and now abandoned.

BACKGROUND OF THE INVENTION

1. The Field of the Invention

This invention relates to novel benzaldehydes having a silver halidedeveloping capability and which are particularly useful as intermediatesfor the preparation of yellow azo methine dyes having particularlydesirable performance characteristics in photographic products andprocesses.

2. Description of the Prior Art

Yellow dyes having a silver halide developing capability, e.g., a silverhalide developing substituent are known to the art. Such dyes, commonlyreferred to as "dye developers", are disclosed in the following U.S.Pat. Nos.: 3,134,672; 3,134,764: 3,135,604; 3,135,734; 3,141,772;3,183,090; 3,309,199; 3,424,742; 3,597,200; 3,705,184 and 3,752,836.

Of the above Patents, U.S. Pat. Nos. 3,597,200; 3,705,184 and 3,752,836particularly relate to yellow dye developers having azomethine dyeschrome complexed to a substantially colorless ligand which provides thesubstituent having the silver halide developing capability. The yellowazomethine dyes of these Patents are of the following general formula:##STR2## where the alkoxy moiety contains 1-8 carbon atoms and n and meach are the integers 1 or 2.

As described in these Patents and particularly in U.S. Pat. No.3,705,184, the yellow ortho, ortho' dihydroxy azomethine dyes of Formula1 can be prepared by reacting an alkoxy-substitutedo-hydroxybenzaldehyde with a nitro-substituted o-hydroxyanilineaccording to the following reaction scheme: ##STR3##

As also disclosed in these Patents, the yellow ortho, ortho' dihydroxyazomethine dyes of Formula 1 can be chrome-complexed with asubstantially colorless ligand to provide 1:1 chrome-complexed yellowdye developers. The particularly preferred 1:1 chrome complexed yellowdye developers are those of the following general formula: ##STR4##where, m and n are 1 or 2, (alkoxy) has from 1-8 carbon atoms and--alkylene-- has from 1-6 carbon atoms.

1:1 chrome complexed yellow azomethine dyes of the above Formula 2 haveexcellent performance characteristics in terms of color as well asstability. In fact, a chrome complexed azomethine of Formula 2 whichconforms to the following specific formula has enjoyed extensive successin commercial diffusion transfer, photographic film units. ##STR5## Witheach --OC₃ H₇ being normal propanol.

This invention presents to the art novel benzaldehydes having a silverhalide developing substituent. These novel benzaldehydes are valuableintermediates particularly useful in the preparation of yellowazomethine dyes having a silver halide developing capability andespecially chrome complexed yellow azomethine dye developers havingperformance characteristics substantially equivalent to and in somerespects, superior to yellow azomethine dye developers known to the art.

SUMMARY OF THE INVENTION

The novel benzaldehydes of the present invention are those of thefollowing general formula: ##STR6## Where: n¹ is the integer 1-8, eachOR¹ is hydroxy or a protective group such as an acyloxy, benzyloxy,ethyloxy, alkoxy, acetoxy or like groups which can be converted orremoved such as by hydrolysis to provide the dihydroxy phenyl silverhalide developing moiety or substituent, the particularly preferred R¹groups being carbomethoxy or carboethoxy and R² can be a substituentsuch as alkyl, alkoxy or halogen and benzaldehydes having suchsubstituents are included within the scope of the claims.

The novel benzaldehydes of Formula 4 are valuable intermediatesparticularly useful in the preparation of yellow azomethine dyes havinga silver halide developing capability. An illustrative preparation ofsuch yellow dyes is as follows: ##STR7##

Representative preferred yellow azomethine dyes of Formula 5 include thefollowing: ##STR8## Where each OR¹ in the above formulae is --OH,--0C0₂CH₃, or --OCO₂ C₂ H₅.

As can be seen from Formulae 6-10, the yellow ortho, ortho' azomethinedyes produced from the novel benzaldehydes of the present invention areactually dye developers. That is, the dyes have a silver halidedeveloping substituent as an integral part of the organic dye molecule.This feature of having a silver halide developing capability as anintegral part of the dye provides distinct advantages particularly inthe formation of metal complexes of the yellow dye developers with othercomplexable dyes or ligands and particularly with dyes or ligands alsohaving silver halide developing substituents. For example--as will beillustrated later--a 2:1 chrome complexed yellow azomethine dyedeveloper of Formula 11 shown below has especially desirable performancecharacteristics in photographic products and processes particularly interms of color stability. ##STR9## Where: M is any cation that does notimpair photographic processing of the dye developer and can be amongothers, H₃ O, a metal ion, or a quaternary ammonium salt including oniumsalts as an integral part of the dye moiety and, R², n¹ and m are asdefined before.

The invention, as well as details relating to the manners for making andusing it, will be more fully appreciated by the following description ofthe preferred embodiments taken with FIGS. 1-5.

DESCRIPTION OF THE DRAWINGS

FIGS. 1-3 are simplified, schematic views of arrangements of essentialelements of film units having dye developers prepared from the novelbenzaldehydes of this invention. The film units are shown after exposureand processing.

FIGS. 4 and 5 graphically depict dye stability data obtained in Examples9 and 11 respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The preferred preparation of the novel benzaldehydes of the presentinvention essentially involves two steps. The first step involvesreacting a di-OR' substituted phenyl alcohol with a p-toluene sulfonylchloride (tosyl chloride) and this first step can be illustrated by thefollowing general reaction scheme: ##STR10##

The second step involves the reaction of the tosylate product of step 1(Formula 14) with a metal bis (resorcaldehyde) and this reaction can beillustrated by the following general reaction scheme: ##STR11##

The metal bis (resorcaldehyde) of Step 2 (Formula 16) can be prepared bythe reaction of a dihydroxybenzaldehyde with a metal (preferably copper)acetate monohydrate according to the following general reaction scheme:##STR12##

Details relating to the synthesis involved in the preparation of thenovel benzaldehydes of this invention and to the preparation of 2:1chrome complexes of the dye developers using the novel benzaldehydeswill be better appreciated by reference to the following illustrativeexamples.

EXAMPLE 1

This example illustrates a preparation of an intermediate used inpreparing a compound of Formula 12. The illustrative preparationinvolves the following reaction scheme: ##STR13##

Step 1

The following ingredients were placed in a 5 liter 3 neck flask:

    ______________________________________                                        2,5-dimethoxybenzaldehyde                                                                             447 grams                                             malonic acid            559 grams                                             pyridine               1080 grams                                             ______________________________________                                    

The mixture was heated to 50° C. to obtain solution; then 40 mls. ofpiperdine were added and the reaction mixture heated at 80°-85° C. for 2hours followed by refluxing for an additional 3 hours. The solution wascooled (overnight), poured into 11 liters of H₂ O and acidified slowlywith 1 liter conc. HCl. to provide the product dimethoxy cinnamic acidwhich was filtered and washed with water.

Step 2

The following ingredients were placed in a 2 liter Parr bottle:

    ______________________________________                                        dimethoxy cinnamic acid                                                                               200 grams                                             isopropyl alcohol      1100 mls.                                              Pd/BaSO.sub.4 (5%)      10 grams                                              ______________________________________                                    

The hydrogenation of the dimethoxy cinnamic acid was carried out totheoretical uptake. The catalyst (Pd/BaSO₄) was filtered and thesolution was treated with activated charcoal and then stripped todryness to recover the dimethoxy hydrocinnamic acid.

Step 3

5.3 kgs. of 2,5-dimethoxyhydrocinnamic acid were dissolved in 5 liters48% HBr solution. The reaction mixture was brought to reflux to distilloff all the low boiling material up to 120° C. Refluxing was continuedfor about 3 hours. After cooling the mixture to room temperature, theprecipitate was filtered off and washed well with water.

Step 4

A solution of 730 gms. NaOH in 12.5 liters H₂ O was deaerated and keptunder a blanket of nitrogen; then, 750 gms. of the lactone formed inStep 3 were added to it. The reaction mixture was stirred at roomtemperature for 2 hours and then cooled to 10° C. 2.0 kgms. methylchloroformate were added at a slow enough rate to maintain thetemperature at 10° C. The reaction mixture was stirred for an additional1/2 hour and acidified to pH 2.0 with 1.8 liter 10% HCl solution. Thewater was decanted from the oil which formed, the oil was allowed tosolidify slowly (overnight) to provide a crude yield ofdicarbomethoxyphenyl propionic acid.

The crude yield of dicarbomethoxyphenyl propionic acid was purified bydissolving 200 gms. of the product of Step 4 in 2 liters of ligroin. Thesolution was heated to 80° C. and 1 liter benzene was added to dissolvethe crude while the temperature was maintained at 80° C. The solutionwas treated with activated charcoal and filtered hot. On cooling, thepure product precipitated out. (Some oil formed at first but solidifiedon standing.) The product was then filtered and washed with hexane.

EXAMPLE 2

This example illustrates a preparation of a compound of Formula 12 andparticularly relates to a preparation of a 3-(2', 5'dicarbomethoxyphenyl) propanol (Formula 19). The illustrativepreparation involves the following reaction scheme: ##STR14##

A nitrogen atmosphere was maintained by slowly flowing N₂ through a 2liter, three neck flask while 68.08 gms dicarbomethoxyphenyl propionicacid (Formula 18) (0.2087 M) was added to 543 mls of anhydroustetrahydrofuran. The dicarbomethoxyphenyl propionic acid dissolvedreadily and the solution was slowly stirred at 20°-25° C. Whilemaintaining a slow flow of N₂ and maintaining the solution at atemperature of about 21° C., 18.40 gms (0.23 M) of borane methyl sulfidewas added slowly over 1/2 hour with good stirring.

The slow flow of N₂ was continued while the mixture was stirred for41/2-5 hours at about 21° C. Then, 315 mls of methanol were added slowlywith stirring to convert any excess borane to volatile borates.

The mixture was then filtered and volatiles were stripped off on arotary evaporator using high vacuum and a hot water bath. The yield was64.5 gms. of a clear yellow viscous liquid which eventually crystallizedto a white solid soluble in CHCl₃ and methanol. The yield obtained was98.7% of theoretical.

EXAMPLE 3

This example illustrates a preparation of a compound of Formula 15 andparticularly relates to preparation of 3-(2', 5'-dicarbomethoxyphenyl)propyl-p-tosylate. The illustrated preparation involves the followingreaction scheme. ##STR15##

67.5 gms. of the dicarbomethoxyphenyl propionic alcohol (Formula 19)were dissolved at room temperature in 1220 mls. of pyridine in a 2 literflask. The solution was then cooled to 0° C. While stirring the solutionand maintaining the temperature at about 0° C., 82.5 gms. ofp-toluenesulfonyl chloride were added as a solid, portion wise. Afterthe addition, the mixture--tightly sealed to keep dry--was keptovernight in a refrigerator at 3° C.

The reaction mixture was then precipitated by adding the mixture to awell stirred cold dilute aqueous HCl solution (7,800 mls, ice colddistilled water plusl,520 mls conc. HCl.) and continuing the stirringfor 11/2 to 2 hours. The precipitate was oily at first but graduallybecame solid with stirring and trituration. The water was decanted, colddilute HCl added again and stirring and trituration continued foranother 11/2 to 2 hours. A white solid was filtered off, washed withwater and air dried overnight at room temperature. (The product shouldnever be heated above room temperature.) Product yield was 100.7 gms. ofwhite solid, m.p. 75°-76° C. and soluble in methylene chloride. Theproduct should be stored at temperatures of 3° C. or lower.

    ______________________________________                                        Properties of                                                                 Compound:                                                                              MOL.WT.: 466.49                                                                            MOL.FORMULA: SO.sub.9 C.sub.22 H.sub.26                 m.p.     Color and State:                                                                           Solv.:                                                  75°-75.5° C.                                                             White Solid  Methylene Chloride, CHCl.sub.3                          ______________________________________                                    

Elemental Analysis: Found: 56.86%C; 5.72%H; 6.71%S: Theory: 56.64%C,5.62%H; 6.87%S.

EXAMPLE 4

This example illustrates a preparation of a compound of Formula 16 andparticularly the preparation of cupric bis(resorcaldehyde). Theillustrated preparation involved the following reaction scheme:##STR16##

19.97 gms (0.1 M) of cupric acetate monohydrate were dissolved in a roomtemperature solution of 50% aqueous methanol and the solution wasgravity filtered to remove trace insolubles.

27.62 gms (0.2 M) of 2,4-dihydroxybenzaldehyde were dissolved in 50%aqueous methanol warmed slightly on a steam bath; the solution was thencooled to room temperature.

The 2,4-dihydroxybenzaldehyde solution was added to the well stirredsolution of cupric acetate monohydrate and a green solid productprecipitated almost immediately, but stirring was continued at roomtemperature for about one hour.

The product was filtered, washed several times with water; then severaltimes with methanol and finally, several times with ether. The productwas dried for one hour at 60° C. and 31.06 gms of a light green solidwere obtained (91.96% theoretical yield).

EXAMPLE 5

This example illustrates a preparation of a compound of Formula 4 andparticularly a preparation of a 2hydroxy-4-[3'(2",5"-dicarbomethoxyphenyl)-n-propoxyl]benzaldehyde. Theillustrated preparation involves the following reaction scheme:##STR17##

16.90 gms. of cupric bis(resorcaldehyde) (Formula 21) were dissolved in170 mls. hexamethyl phosphoric triamide in a 1 liter flask having N₂flow, 4.11 gms of a 57% NaH/oil mixture were added carefully with goodstirring; there is a slight exotherm and some foaming due to H₂evolution. Stirring was continued for 21/2 hours at which time a darkgreen solution was obtained. 43.84 gms of 3-(dicarbomethoxyphenyl-Ppropyl-p-tosylate (Formula 20) dissolved in 180 mls.hexamethylphosphoric triamide were added to the green solution and theresulting solution was stirred overnight at room temperature and under aN₂ flow.

The product was precipitated in 10 volumes cold, dilute aqueous HClsolution and then extracted from the oily mixture by shaking it threetimes with ether. The final ether solution was shaken with aqueous Na₂CO₃ and then with water. The product was then dried with anhydrousMgSO₄. 33.40 gms of product was obtained as a viscous yellow-tansemi-solid. (82.60% of theoretical yield).

The dicarbomethoxy protective groups of the product of this Example canbe removed by hydrolysis with mineral acids in manners known to the artto provide the compound of the following formula: ##STR18## However inthe preferred preparations of yellow azomethine dyes of Formula 5 whichfollow, the protective groups are retained and removed later.

EXAMPLE 6

This example illustrates the preparation of a yellow azomethine dye ofFormula 5 and particularly illustrates the preparation of a compound ofthe following formula: ##STR19##

The illustrated preparation involves the following reaction scheme:##STR20##

In a 500 ml flask with a magnetic stirrer, reflux condenser and dryingtube, 25.37 gms of 2 hydroxy-4-[3' (2", 5|dicarbomethoxyphenyl)-n-propyl] benzaldehyde were dissolved in 102 mlsrefluxing methanol. 9.67 gms of 4-nitro-2-aminophenol dissolved in 39mls of hot methanol were added to the benzaldehyde solution. In lessthan a minute, a very heavy yellow precipitate came out of solution.Stirring and refluxing were continued for 2 hours.

The mixture was cooled to about 0° C. and the yellow solid productfiltered off and dried to constant weight giving 20.18 gms ofyellow-orange product. (59.5% theoretical yield).

    ______________________________________                                        Properties of                                                                           Color & State:                                                                             Soly.:                                                 Compound:                                                                               Yellow-Orange                                                                              DMF;DMSO;Warm THF;                                               solid        Warm Dioxane.                                          UV.Visible:                                                                   Solvent   λ max 460 nm                                                 DMF       ε max 26,400                                                ______________________________________                                    

EXAMPLE 7

This example illustrates a preparation of a 2:1 chrome complex of theproduct of Example 6. The illustrated preparation involves the followingreaction scheme: ##STR21##

19.77 gms of the compound of Formula 24, 9.04 gms of (CH₃ COO)₃ Cr H₂ O,181 mls methyl cellosolve and 11.11 gms of triethylamine were added to a3 neck flask having a magnetic stirrer and reflux condenser with dryingtube. The mixture was stirred and heated at 95° to 100° C. for 13/4hours until a solution was obtained. The solution was then refluxed for15 to 20 minutes.

The reaction solution was precipitated by stirring the solution in 2liters of cold dilute aqueous HCl solution. The yellow solid product wasfiltered off and washed several times with distilled water. Yield ofproduct was 18.78 gms of a tan solid (89.5% theoretical yield).

    ______________________________________                                        Properties of                                                                           Color & State:                                                                             Soly.:  Methyl Cellosolve,                             Compound                       DMF, DMSO                                                Tan-solid                                                           UV,Visible:                                                                             λ max 445 nm                                                 Solvent   ε max 41,500                                                ______________________________________                                    

EXAMPLE 8

This example illustrates a procedure for converting the dicarbomethoxygroups of the 2:1 chrome complex of Example 7 to dihydroxy groups toprovide the 2:1 chrome complexed yellow azomethine dye developer of thefollowing formula: ##STR22##

The illustrated procedure involves the following reaction scheme:##STR23##

18.00 gms of the 2:1 chrome complexed dye of Formula 30 were dissolvedin 200 mls methyl cellosolve at room temperature. N₂ bubbled into thesolution to deaerate it. Then with N₂ slowly passing over the solution,250 mls of a 5% (aqueous) NaOH solution, also deaerated, was graduallyadded with good stirring. There is a very mild exotherm. The solutionwas stirred under slow N₂ flow for 45 minutes plus 15 minutes while itwas cooled down to about 5° C. 500 mls of cold 10% (aqueous) HClsolution (also deaerated) was added slowly to the well stirred coldreaction solution and the yellow tan solid product precipitated out. Theproduct was filtered off, washed several times with distilled water anddried to constant weight. Product yield was 14.79 gms of tan solid.

    __________________________________________________________________________    Properties of                                                                 Compound:    MOL.WT.: 915.79                                                                           MOL.FORMULA:                                                                  CrN.sub.4 O.sub.15 C.sub.44 H.sub.39                              Color & State:                                                                Tan Solid   Soly.: Methyl                                                                 Cellosolve; CMF;                                                              DMSO; dilute                                         UV,Visible:  PANo.       aqueous alkali                                                    20,362 λ = 445 nm                                         Solvent      ε = 38,000                                               Methyl Cellosolve                                                             Elemental                                                                     Analysis:                                                                           Found:                                                                             55.68%C                                                                            4.54%H                                                                             5.73%N                                                                             5.51%Cr                                                                            10.45%ASH                                      Product +                                                                     2H.sub.2 O of                                                                       Theory:                                                                            55.52                                                                              4.55 5.89 5.46                                                Hydration                                                                     __________________________________________________________________________

Yellow azomethine dye developers prepared from the novel benzaldehydesof this invention are particularly useful in diffusion transferphotographic products and processes. The chrome complexed azomethine dyedeveloper of Example 8 has been found to be particularly advantageouswhen used in integral negative positive film units of the type discribedin detail in U.S. Pat. Nos. 3,415,644 and 3,647,437.

A representative film unit of this type is shown as 10 FIG. 1 andincludes a light-reflecting layer provided by a light-reflecting pigmentin a processing composition initially present in a rupturable processingcontainer (not shown) and distributed after photosensitive layer(s) 14is photoexposed through transparent support 20 and image-receiving layer18. Processing compositions used in such film units are aqueous alkalinephotographic processing compositions comprising an opacifying systemwhich include a titanium dioxide pigment as the light-reflecting agent,preferably in combination with an optical filter agent described indetail in U.S. Pat. No. 3,647,437. When the processing composition isdistributed over photoexposed portions of photosensitive system 14, alight-reflecting layer 16 comprising the titanium dioxide is providedbetween image-receiving layer 18 and photosensitive layer 14.Application of the processing composition initiates development ofphotoexposed photosensitive layer(s) 14 in manners well known to the artto establish an image-wise distribution of diffusible image-providingmaterial which can comprise silver but preferably comprises one or moredye image-providing material. The diffusible image-providing material(s)is transferred through permeable, light-reflecting titaniumdioxide-containing layer 16 where it is mordanted, precipitated orotherwise retained in known manner in image-receiving layer 18. Thetransfer image is viewed through transparent support 20 againstlight-reflecting layer 16.

FIG. 2 shows an arrangement of essential elements of an integralnegative-positive film unit of the type described in U.S. Pat. No.3,594,165 and British Pat. No. 1,330,524 following exposure andprocessing. The film unit 10a includes a processing compositioninitially retained in a rupturable container (not shown) and distributedbetween cover sheet 22 and photosensitive system or layer 26 afterphotoexposure of photosensitive layer(s) 26 through transparent coversheet 22. Processing compositions used in such film units are aqueousalkaline photographic processing compositions which include anopacifying system comprising an opaque pigment which need not be--andusually is not--light-reflecting. After distribution of the processingcomposition between transparent cover sheet 22 and photo-exposedphotosensitive layer 26, an opaque layer 24 is installed which protectslayer 26 from further photoexposure through cover sheet 22. Like thefilm units of FIG. 1, as an after opaque layer 24 is installed, andprocessing composition initiates developing of photoexposedphotosensitive layer 26 to establish an image-wise distribution of theimage-providing materials in manners well known to the art. For example,the processing composition alone may cause development or developingagents may be in the processing composition initially and/or the agentsmay be in the film unit so that they may be carried to layer 26 by theprocessing composition. The imagewise distribution is transferredthrough permeable titanium dioxide containing reflecting layer 28 to dyeimage layer 30 for viewing through transparent support 32 against thereflecting pigment containing layer 28. Oftentimes an opaque layer (notshown) is positioned between light reflecting layer 28 andphotosensitive layer 26.

The novel yellow dye developers of the present invention also may beutilized in film units designed to be separated after processing, suchas those described in U.S. Pat. No. 2,983,606. Such a diffusion transferfilm unit of the present invention is shown in FIG. 3 as 10b. The filmunit shown there comprises a photosensitive element having an opaquesupport 40 carrying a photosensitive system containing layer(s) 42. Infilm units of this type the photosensitive element is photoexposed and aprocessing composition 44 is then distributed over the photoexposedsystem. During processing an image-receiving element comprising dyeimage layer 46 carried by support 50--preferably opaque--is superposedon the photoexposed photosensitive element. Like the film units of FIGS.1 and 2, the processing composition permeates layer(s) 42 to provide animagewise distribution of diffusible dye image-providing materials whichis transferred to dye image layer 46. Unlike the film units of FIGS. 1and 2, however, the transferred dye image is viewed in layer 46 againstlight-reflecting background 48 after separation of the image-receivingelement from the photosensitive element.

Example 9 which follows presents a comparison of the performancecharacteristics of the 2:1 chrome complexed yellow dye developer ofFormula 26 and a 1:1 chrome complexed yellow dye developer extensivelyused in commercial film units (the 1:1 chrome complexed dye developer ofFormula 3) The comparison involved diffusion transfer film units of thetype shown in FIG. 1 and having a multicolor photo-sensitive elementswhich contained the following cyan and magenta dye developers: ##STR24##

Also, except for variations in the yellow dye developer layer which areexplained in Example 9, the photosensitive elements of the film units ofExample 9 were prepared by coating a gelatin-subcoated, 4 mil, opaquepolyethylene terephthalate film base with the following layers:

1. a layer of cyan dye developer and 2-phenylbenzimidazole (antifoggant)dispersed in gelatin and coated at a coverage of about 58 mgs./ft.² dye,about 22 mgss/ft.² of 2-phenyl benzimidazole and about 112 mgs./ft.² ofgelatin;

2. a red-sensitive gelatino silver iodobromide emulsion coated at acoverage of about 80 mgs./ft.² of silver and about 104 mgs./ft.₂ ofgelatin;

3. a layer of a 60-30-4-6- tetrapolymer of butylacraylate, diacetoneacrylamide, styrene and methacrylic acid and polyacrylamide coated at acoverage of about 428 mgs./ft.² of the copolymer and about 23 mgs./ft.²of polyacrylamide;

4. a layer of magenta dye developer and 2-phenyl benzimidazole dispersedin gelatin and coated at a coverage of about 60 mgs./ft.² of dye, about21 mgs./ft.² of 2-phenyl benzimidazole and about 40 mgs./ft.² ofgelatin;

5. a green-sensitive gelatino silver iodobromide emulsion coated at acoverage of about 30 mgs./ft.² of silver and about 43 mgs./ft.² ofgelatin;

6. a layer containing the tetrapolymer referred to above in layer 3 andpolyacrylamide coated at a coverage of about 230 mgs./ft.² of copolymerand about 20 mgs./ft.² of polyacrylamide;

7. a layer of a yellow dye developer and 2-phenyl benzimidazoledispersed in gelatin and coated at the coverage specified in Example 9.

8. a blue-sensitive gelatino silver iodobromide e emulsion layer coatedat a coverage of about 110 mgs./ft.² of silver and about 52 mgs./ft.² ofgelatin and

9. a layer of carbon black dispersed in gelatin coated at a coverage toprovide about 4 mgs./ft.² of carbon black and about 40 mgs./ft.² ofgelatin.

The image-receiving elements of the film units of Example 9 wereprepared by coating a transparent 4 mil polyethylene terephthalate filmbase with the following layers:

1. as a polymeric acid layer, the partial butyl ester ofpolyethylene/maleic anhydride copolymer at a coverage of about 2,500mgs./ft.² ;

2. a timing layer containing about 40:1 ratio of a 60-30-4-6 tetracopolymer of butylacrylate, diacetone acrylamide, styrene andmethacrylic acid and polyvinyl alcohol at a coverage of about 500mgs./ft.² ; and

3. a polymeric image-receiving layer containing a 2:1 mixture, byweight, of polyvinyl alcohol and poly-4-vinylpyridine, at a coverage ofabout 300 mgs./ft.².

The so prepared image-receiving and photosensitive elements can be tapedtogether with opaque tape extending around the edges to provide anintegral film unit. A rupturable container retaining an aqueous alkalineprocessing solution was mounted in a fixed position on the leading edgeof each of the elements, by pressure-sensitive tapes, so that, pressureapplied to the container would rupture the container's marginal seal andits contents could be distributed between the image-receiving layer andthe gelatin overcoat layer of the photosensitive element.

In each of the film units of Example 9, the aqueous alkaline processingcomposition comprised:

    __________________________________________________________________________    Water                                  1918                                                                             cc                                  Potassium hydroxide (85%)              509                                                                              g.                                  N-phenethyl-α-picolinium                                                bromide (50% solution in water)        110.4                                                                            g.                                  Carboxymethyl cellulose                                                       (Hercules Type 7H4F providing                                                 a viscosity of 3,000 cps. at                                                  1% in water at 25° C.) 95% solids                                                                             80.3                                                                             g.                                  Titanium dioxide                       1842                                                                             g.                                  6-methyl uracil                        9.3                                                                              g.                                  bis-(β-aminoethyl)-sulfide        1.4                                                                              g.                                  Lithium nitrate                        4.8                                                                              g.                                  Benzotriazole                          34.6                                                                             g.                                  Colloidal silica aqueous                                                      dispersion (30% SiO.sub.2)             77.6                                                                             g.                                  N-2-hydroxyethyl-N,N',N'-tris                                                 carboxymethyl-ethylene diamine         36.4                                                                             g.                                  Polyethylene glycol                                                           (molecular weight 6,000)               22.7                                                                             g.                                  4-amino pyrazolo pyrimidene            11.3                                                                             g.                                   ##STR25##                             93.4                                                                             g.                                   ##STR26##                             20.8                                                                             g.                                  __________________________________________________________________________

The photosensitive element of such prepared integral film units may beexposed through the transparent support of the image-receiving element,and a layer of the processing composition may be distributed by passingthe film unit between a pair of pressure-applying rolls.

EXAMPLE 9

This example presents a comparison of dye stability measurements for twofilm units, one containing a 1:1 chrome complexed yellow dye developerof the prior art and the other containing a 2:1 chrome complexed yellowdye developer of this invention. FIG. 4 graphically depicts the dyestability measurements. The two film units had multicolor photosensitiveelements prepared as described before and were substantially identicalexcept for the yellow dye developer layers. In the film unit designatedas 2069-140 of FIG. 4, the yellow dye containing layer contained the 2:1chrome complexed yellow dye developer of Formula 26 and 2-phenylbenzimidazole dispersed in gelatin at a coverage of about 46 mgs./ft.²yellow dye developer, about 19.6 mgs./ft.² of 2-phenyl benzimidazole andabout 18.1 mgs. gelatin. The film unit designated as 2069-130 of FIG. 4had a yellow dye developer containing layer which contained the 1:1chrome complexed yellow dye developer of Formula 3, 2-phenylbenzimidazole and gelatin at a coverage of about 67 mgs./ft.² yellow dyedeveloper, about 18 mgs./ft.² phenyl benzimidazole and about 33mgs./ft.² gelatin. It will be noted that the coverages of yellow dyedevelopers in each film unit are different (46 mgs./ft.² v. 67mgs./ft.²). This difference, however, was intended and is based onconsiderations involving such factors as the extinction coefficient, themolecular weight and the molecular structure of each dye developer toestimate coverages for each dye developer which can provideapproximately equivalent yellow optical densities for each exposed andprocessed film unit.

The film units were exposed to two meter candle seconds through a yellowfilter and processed by passing each film unit between a pair ofpressure-applying rolls to thereby distribute a layer of processingcomposition about 0.0028" thick between the image-receiving layer andthe gelatin/carbon black overcoat of the photosensitive element. Undersuch exposure conditions only yellow dye was transferred to theimage-receiving layer and both processed film units had comparableyellow colored images.

The processed film units were maintained at room temperature fortwenty-four hours and then the dye stability of each unit was determinedby exposing each unit to the condition of a Xenon Arc Weatherometer overa period of 40 days and periodically measuring the percent yellow dyeretained for each unit. During this forty day period, the light outputfor the Weatherometer ranged between 7000 to 9000 foot candles. FIG. 4graphically depicts the data obtained over the forty day period and thedata shows improved stability performance characteristics for the 2:1chrome complexed yellow dye developer of this invention.

EXAMPLE 10

This example illustrates a preparation of a 1:1 chrome complexazomethine yellow dye developer of the present invention. Theillustrated preparation involves the following reaction schemes:##STR27##

Step 1

The following ingredients were added to a 2-liter, 3-neck, round bottomflask having a vertical reflux condenser and a N₃ inlet and outlet:

    ______________________________________                                        Cr Cl.sub.3 . 6H.sub.2 O                                                                              25.03 gms.                                            Dimethyl formamide (anhydrous)                                                                        409 mls.                                              Benzene (anhydrous)     588 mls.                                              ______________________________________                                    

The solution was refluxed with stirring to azeotrope out water withbenzene (13.8 mls. H₂ O collected) and then all benzene was distilledoff.

26.7 gms. of the compound of Formula 24 were added to the anhydrous CrCl₃ /dimethyl formamide solution, and the mixture was refluxed for 45minutes.

The reaction solution was cooled and precipitated into 6,700 mls.distilled water and stirred for about 20 minutes. The precipitate wasfiltered and washed twice on the funnel with room-temperature, distilledwater. After air-drying overnight, the precipitate was placed in an ovenheated to 67° C. for 15 minutes and then placed in a vacuum oven heatedto 52° C.; a high vacuum was pulled for about 21/2 hours. Yield ofproduct (Formula 27) was 20.71 gms. of a yellow-tan powder (69.12%theoretical).

Step 2

A round-bottom, 250 ml. flask having a magnetic stirrer, a verticalreflux condenser and a N₂ inlet and outlet was flushed with dry N₂ whileheated at 75° to 80° C. The following ingredients were then added:

    ______________________________________                                        Compound of Formula 27   7.00 gms.                                            Compound of Formula 28 (98% pure)                                                                      2.80 gms.                                            IR-45 Amberlite Ion Exchange Resin                                                                     0.58 gms.                                            Methyl cellosolve        90 mls.                                              ______________________________________                                    

The reaction mixture was stirred at 75°-80° C. for a total of 10 hours.The ion exchange resin (insoluble) was filtered off, and the solutionwas sealed under N₂ overnight at room temperature. The product wasprecipitated by adding the solution (slowly) to 1,800 mls. distilledwater at room temperature with good stirring. A fine yellow precipitatewas filtered off, stirred well in 500 mls. distilled water and filteredagain. The product was placed in a vacuum oven heated to 55° C. (withdrierite present) and a high vacuum was pulled on the oven for about31/2 hours. Yield of product (Formula 29) was 8.58 gms. of yellow powder(88.50 theoretical).

Step 3

The following ingredients were added to a 1-liter, 3-neck, round-bottomflask having a magnetic stirrer, N₂ inlet and outlet and droppingfunnel:

    ______________________________________                                        Compound of formula 29 8.30 gms.                                              Methyl cellosolve      80 mls.                                                ______________________________________                                    

N₂ was bubbled through the solution to deaerate it, and the system wasflushed with N₂. A solution containing 15.02 gms. Na OH in 142 mls. H₂ Owas placed in the dropping funnel and deaerated. While stirring thesolution in the flask and with an N₂ flow through the flask, the Na OHsolution was added slowly (a slight exotherm was noted). The contents ofthe flask were stirred at room temperature for about 55 minutes.

The flask was then cooled in an ice bath; and, while stirring and withan N₂ flow, a cold dearated solution of 31.05 mls. concentrated HCl in280 mls. H₂ O was added (slowly). The product precipitated out as a tansolid which was filtered off and air-dried.

After drying, the product--now a tan-yellow solid--was stirred in 150mls. distilled water, filtered and placed in a vacuum oven (drierite waspresent) for 5 hours. The vacuum oven was heated to a temperature of48°-50° C., and a high vacuum was pulled on the oven. Yield of yellowpowder (Formula 30) was 6.87 gms. (98.91% theoretical).

    ______________________________________                                        Properties of                                                                              Color & State:                                                                             Soly.:                                              Compound:                                                                                  Yellow-tan   Methanol, DMF                                                    Solid powder Methyl cellosolve                                   U.V. Visible:                                                                 Solvent      max 443                                                          Methyl cellosolve                                                                          max 18,400                                                       ______________________________________                                    

EXAMPLE 11

This example presents a comparison of the light stabilitycharacteristics of the 1:1 chrome complexed yellow dye developer ofExample 10 and the 1:1 chrome complexed yellow dye developer of Formula3. This comparison involved diffusion transfer monochrome film unitswhich had substantially the same image receiving elements, the sameprocessing compositions and the same photosensitive elements--except forthe yellow dye developer used. The film unit designated as 22-092 inFIG. 5 had a yellow dye developer layer comprising the dye developer ofExample 10 dispersed in gelatin and coated at a coverage of about 40mgms/ft² dye developer and about 210 mgms/ft² gelatin.

The film units were exposed to two meter candle seconds through a yellowfilter and processed by passing each film between pressure-applyingmembers to distribute a layer of processing composition about 0.0022"thick between the image-receiving element and the photosensitiveelement. Both processed film units had comparable yellow color. Dyestability measurements were made as described in Example 9 except thateach film unit was dried for three days at 120° F. before being placedin the arc. FIG. 5 graphically depicts the data obtained over aforty-seven day period and the data indicates that the dye developer ofExample 10 had substantially better stability performancecharacteristics than the dye developer of Formula 3.

From the above description, it should be apparent that the presentinvention presents to the art novel benzaldehydes particularly useful inpreparing yellow dye developers having a desirable degree of performancecharacteristics in terms of color as well as stability. Accordingly,many modifications can be made in details of the above examples offeredfor the purposes of illustrating preferred embodiments of the inventionwithout departing from the spirit and scope of the invention defined inthe claims.

What is claimed is:
 1. A process for the synthesis of benzaldehydescomprising reacting a compound represented by the formula ##STR28## witha compound represented by the formula ##STR29## to form a compoundrepresented by the formula ##STR30## wherein each OR¹ group is hydroxyor a protective group which can be converted or removed to provide adihydroxyphenyl moiety, R² may be alkyl, alkoxy or halogen, and n' is aninteger from 1 to
 8. 2. A process as defined in claim 1 wherein R¹ ishydrogen, carbomethoxy or carboethoxy.
 3. A process as defined in claim1 wherein the compound formed is represented by the formula ##STR31## 4.A process as defined in claim 1 wherein the compound formed isrepresented by the formula ##STR32##
 5. A process as defined in claim 1wherein the compound formed is represented by the formula ##STR33##
 6. Aprocess as defined in claim 1 wherein the compound formed is representedby the formula ##STR34##
 7. A process as defined in claim 1 wherein thecompound formed is represented by the formula ##STR35##
 8. A process asdefined in claim 1 wherein the compound formed is represented by theformula: ##STR36##